bitbake: command: Fix getCmdLineAction bugs

Executing "bitbake" doesn't get a sane message since the None return value
wasn't being handled correctly. Also fix msg -> cmd_action['msg'] as
otherwise an invalid variable is accessed which then crashes the server
due to the previous bug.

(Bitbake rev: c6211291ae07410832031a5274690437cc2b09a6)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/command.py

@@ -148,8 +148,10 @@ class CommandsSync:
         Get any command parsed from the commandline
         """
         cmd_action = command.cooker.commandlineAction
-        if cmd_action['msg']:
-            raise CommandError(msg)
+        if cmd_action is None:
+            return None
+        elif 'msg' in cmd_action and cmd_action['msg']:
+            raise CommandError(cmd_action['msg'])
         else:
             return cmd_action['action']